Evan700
New member
Hi everyone, first post here and I need some help with my 03 viper 700. Just went to get it going this year as we finally have snow here in ontario. the problem I'm having is It won't stay idling but I can ride it around with no problems. it will start and high idle at 2000 rpm and its all good but as soon as I rev it, the idle drops to 1400-1500rpm and stalls. I have since taken the carbs off and cleaned the jets very well as I've heard thy can be temperamental but there was no change, I tried to adjust the idle screw but it either idles too low or leans out and holds rpm when reved. let me know if you need anymore info, any suggestions are greatly appreciated.
Clean the pilots again. Remove them and hold them up to a light to make sure you can see through them.
The hole is very small. Either a small torch tip cleaner or a wire on a steel brush will go through.
The hole is very small. Either a small torch tip cleaner or a wire on a steel brush will go through.
how old is fuel filter?
Evan700
New member
I used carb cleaning picks and made 100% Sure they were clear, went through the rest of the with air and brakes clean. adjustment screws on the bottom are 2 turns out, could that be an issue?
Evan700
New member
just bought the sled a couple months ago so I'm not sure. is it worth replacing? wouldn't that cause it to not rev up?
might be too much restriction for the fuel pump to overcome at idle. they are also prone to falling apart in the tank.
Evan700
New member
ok that makes more sense, ill give that a try. is there a way to visually inspect it or should I just replace it?
for the cost of it, just replace it so you know it is good.
Evan700
New member
just ordered the filter, ill install it tomorrow. is it inside the gas tank?
yes. when i do it, i go in through the filler neck with a coat hanger with the white plastic sleeve removed. just make sure you do not get it wrapped around or bind the fuel gauge lever in the tank.
Evan700
New member
noted, ill give it a shot and update tomorrow. thanks for your help
What number is on the pilot jet?
These sleds are getting pretty long in the tooth so it could be a number of things.
The fact that it won't idle seems to indicate that the issue effects all three carbs or it would try to idle on one or two cylinders.
Does it quit because its too lean or too rich? Check by seeing if will idle longer with a bit of choke then its too lean.
Like 74Nitro said check the pilot jet size as maybe someone has changed them for high altitude of running pipes.
Things that come to mind:
If too lean:
-plugged pilot jets and or passages...low speed circuits are very small and any small restriction can create big issues
-fuel pump diaphram cracked or brittle....pump is getting pretty old and they don't last forever
-pulse line from crankcase to fuel pump cracked or loose
-crankcase crankshaft seals damaged or cracked from being dried out
If too rich:
-choke plungers stuck or out of adjustment
-float needle tips are dried out, worn or damaged
-float needle seats rubber o-rings damaged or missing
Just a few items that come to mind.
The fact that it won't idle seems to indicate that the issue effects all three carbs or it would try to idle on one or two cylinders.
Does it quit because its too lean or too rich? Check by seeing if will idle longer with a bit of choke then its too lean.
Like 74Nitro said check the pilot jet size as maybe someone has changed them for high altitude of running pipes.
Things that come to mind:
If too lean:
-plugged pilot jets and or passages...low speed circuits are very small and any small restriction can create big issues
-fuel pump diaphram cracked or brittle....pump is getting pretty old and they don't last forever
-pulse line from crankcase to fuel pump cracked or loose
-crankcase crankshaft seals damaged or cracked from being dried out
If too rich:
-choke plungers stuck or out of adjustment
-float needle tips are dried out, worn or damaged
-float needle seats rubber o-rings damaged or missing
Just a few items that come to mind.
Evan700
New member
I installed the new fuel filter today(didn't go well, line split inside tank). still running about the same but now I have a engine light for YPVS system. could this have something to do with the problem or is It unrelated?
Evan700
New member
seems too lean to me, engine holds rpm when I rev it. like I said I was very thorough cleaning the carbs but I'm tempted to pull them again. when I was replacing the fuel filter today I checked the fuel pump, when I pull it all 3 lines shoot a good amount of fuel out so I don't think that's the problem. Ive already checked the crank seals by shooting some brakes clean around them while running, rpms didn't change so I'm assuming they're ok. I'm going to dig into the power valves tonight and if that's not the issue ill pull the carbs again and probably the pump as well. ill keep you guys updated. thanks for the reply
Evan700
New member
ive just finished cleaning the power valves and the engine light went away. fired It up in garage and It idled perfect for over 5 minutes, I though it was fixed. took it for a quick ride and I'm once again having the same issues, won't idle and leans out, won't even idle with choke. what's the next step? pull the carbs again?
It definitely sounds fuel supply related that it effects all three cylinders. When cleaning the carbs did you remove the float needle seats and check the top hat filters underneath? They are well hidden and can get plugged by old fuel ect. I remove these completely and trash them on our sleds that have them.
Evan700
New member
I've just gone through the carbs again tonight with no luck. I removed those filters like you said, they didn't look dirty at all. mixture screws are all 2 turns out. the number on the jets is 45, would that be correct for southern Ontario? around 1300ft elevation. will probably be pulling them off again tomorrow, anything else specific I should look for?
super1c
Super Moderator
Did u check reeds?
Have you done a compression test on this engine?